In this kind of an image forming apparatus including an imaging unit detachably mounted on the main body of the image forming apparatus, tin plating may be applied, in place of gold plating, to contacts for electrically connecting a communication line between the main body and the imaging unit from a viewpoint of cost reduction.
However, when tin-plated contacts are used, a naturally oxidized film (corrosion) is generated on the surface of the contacts depending on contact force, contact frequency, and environmental conditions such as temperature and humidity, which may lead to degraded reliability.
Accordingly, a switch-contact corrosion removal device has been proposed for example in JP 2007-26992 A, in which upon speculation or detection of corrosion generated on a switch, a corrosion removal current larger than a normal current is applied to remove the corrosion generated at the contacts of the switch. In JP 2005-294200 A, contact-corrosion prevention circuit has been proposed in which as contacts corrode and a contact resistance is increased thereby, an increase of an input signal line potential in a closed state of the contacts is detected so that the contacts are heated with use of a current from a supply voltage side to remove the corrosion.